Electrical connector



Nov. 17, 1964 EISUKE TAKANO ELECTRICAL CONNECTOR 2 Sheets-Sheet l Filed Dec. 24, 1962 BY ISUKE TAKANO INVENTOR.

ATTORNEYS Nov. 17, 964 EISUKE TAKANO 3,157455 ELECTRICAL CONNECTOR Filed Dec. 24, 1962 2 Sheets-Sheet 2 INVENTOR.

EISUKE TAKANO ATTORNEYS United States Patent O &151455 ELECTRECAL CONNEETGR Eisuhe Takano, Tokyo, apan, assignor to Nippon Electric Company Limited, Tokyo, Japan, a corporation of Japan Filed Dec. 24, 1962, er. No. %6,778 9 Ciaims. (Ci. 339-256) This invention relates to electrical connectors.

When interconnecting various electric circuits of two Components, it is important that the connectors employed have good mechanical stability and reliability of connection. Accordingly, it is an object of this invention to provide a Connector having such characteristics by means of a novel COIISIUCOII which employs a coil spring and a tongue shaped plug terminal which is designed for cooperative engagement with said spring.

All of the objects, features and advantages of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conunction with the accompanying drawing, in which FIG. 1 shows a plug member and a receptacle member of an electrical connection constructed in accordance with the invention, FIG. la showing a side elevation of the plug member, FIG. lb showing in vertical section the receptacle member, and FlG. lc showing a cross section taken on the line lc-lc of FG. lb;

FIG. 2 shows the electrical connector in its connected position, FIG. Za showing a vertical section, while FlG. 2b shows a cross section taken on line Zb-Zb of FIG. Za;

FIG. 3 is an exploded View of another plug member and another receptacle spring assembly constructed in accordance with the invention, FIG. Sa showing the plug member, FIG. 3b showing the receptacle terminal member together with a portion of the plug member, FIG. 36 showing a coil spring, and FIGS. 3:1 and 3e showing cross sections taken respectively on lines 3d-3d and 3e-3e of FIG. 3c; and

FlG. 4 shows still another plug and receptacle member constructed in accordance with the invention, and in which FIG. 4:1 shows the plug member, FIG. 4b shows the receptacle member, and FIG. 4c shows a cross section taken on line 4c-4c of FIG. 4b.

Referring first to FlG. la, an electrical connecter constructed in accordance with the invention includes a twisted tongue-shaped plug terminal I made by twisting a suitable metal strip, and a supporting member 2 therefor madeof insulating material which is xedly attached to a portion of the plug terminal l. The supporting member 2 may be provided with a plurality of plug terminals 1 if desired, for making a plurality of connections. Referring next to FIG. lb, a receptacle member shown therein vertical section comprises an insulator structure 5, and a coil spring 3 made by winding' a piano wire' or a WI'C-Of Phosphor bronze, German silver, or other suitable resilient material into a helix having an elliptical cross section as shown in FIG. lc. The coil spring 3 is dsposed in a cylindrical channel provided in the insulator structure 5 and a terminal member 4 is soldered or otherwise attached to the coil spring at its right end, and extends through the right end of the insulator body. The insulator structure 5 may, if desired, include a plurality of the coil springs 3. The surface of the plug terminal 1 and the coil spring 3 are preferably plated with gold, silver, platinum, rhodium or other suitable contact material. i

It will 'oe obvious that connection will be made when the part shown in FIG. la is inserted to the right into the `assembly shown in FIG. lb, as shown in FIG. Za. As

shown in FIG. 2b, which is a cross-sectional View of the receptacle assembly, the coil spring 3 deforms in accord- 3,l57,455 Patented Nov. 17, 1964 ance with the twisted form of the plug terminal 1. Firm contact is made as a result of the Stress that is produced in the individual turns of the coil spring 3 by the twist deformation produced by insertion of the .plug 1. Such twist deformation results in contact by each turn o'f the heliX of the spring 3 with the plug terminal 1 and plays a very important role in enhancing the relia'bility of the overall electrical contact between the opposite ends ofthe Connector. More particularly, the twist of the plug `terminal 1 gives each helical turn of the coil spring 3 a given twist displacement, with the result that the letter 'is brought into contact with the former at two points for each turn; thus for a coil spring 3 having nn mber of turns, contact with the plug terminal 1 will be made at 2n points under ideal conditions. Thus, the plug terminal 1 and the coil spring 3 combination will be `produce very stable electical contact, so that rel-iability of contact is excellent even under conditions of mechanical shock.

Further, contact between the .plug terminal 1 and coil spring 3 at a multiplicity of points makes it possible to attah with relatively low contact :pressure per point of contact, higher reliability of electrical contact than is achieved with the usual contact arrangements in prior art electrical connectors, which conventionally have onl-yone or two contact points. This results in less abrasion o'f the Contacting portions of the plug terminal 1 and coil spring 3 and thereby enhances the useful life of the connector of this invention. This Connector has another merit in that the helical for-m of the coil `spring 3 allows the same to yieldably -deform in accordance with the form of the plug terminal 1. This has the advantage of 'producing only a relatively small bending force on the plug terminal i. Furthermore, the contact pressure given by the twist deformation between the plug terminal 1 and coil spring 3 insures reliability of the contact obtained after connection of the Connector, even though .the plug terminal 1 before insertion thereof into the coil spring 3 may have some distortion in its actual physical dimensions Compared with its ideal shape.

Refen'ing now to FIG. 3 which shows an electrical connector in accordance with another embocliment of the invention, a plug terminal is shown in FIG. Sa which .is a modification of the plug terminal 1 illustrated in FIG. la and includes a siot 6 provided along the center of the tongue-shaped body with a view 'to furnishing the 'plug terminal 1 with resiliency in the direction of its width. After insertion of the plug terminal 1 `into the coil spring 3, elastic deformation of the plugterminal 1 in the direction of the width results in better contact.

in FIG. 317,. a modified receptacle terminal member 4' is provided with a concave portion at its inner end where it is coupled with the coil spring 3 so that the 'concave portion may become engaged with the convex 'end portion of the plug terminal 1 after it has been pushed into the coil spring 3 in the manner i'llustrated. According to this modification, the coil spring 3 may be made shorter than that for use in the above'illustrators where the inner end portion of the terminal member is flat' rather .than concave.

In FG. 36 a modified composite coil' spring is shown and compr'ises two individual interleaved` helical spring& 9 and 10, so that the torsional rig'idity and the reliability of contact between the plug terminal I and the composite coil spring' may be increased. This' is achieved because of the function of the individual springs as' a y pair of twin Contacts independent" of each other beintroduction of the plug terminal ll into the coil spring 3.

Referrng now to FIG. 4, which shows further modifications of the plug terminal 1 and coil spring 3, a plug terminal 11 is provided which is not twisted, see FIG. 4a, while a coilspring 12 is illustrate'd' in FIGS. 4b` and 4c which 'is twisted in lieu thereof., FlG. 4c shows a cross section taken on line c-c'of'FIG. 4b Excellent contact characteris tics are'attained whentthe plug terminal 11 is pushed into the coil spring 12. i

While the foregoing description sets forth the princples of theinvention in connection with specific apparatus, it

isto be understood that the description is made only by i way of example and not as a limitation of the scope of `the invention as setforth in the objects thereof and inthe accompanying claims. V I

What is claimed is: 1. An electrical Connector comprising at least one helically wound metal spring member having a portion with an elliptical'cross section, and an elongate metal V plug member adapted for insertion into' said spring member, one of said members being axia'lly twisted, said plug member having a set of opposi te edges for engaging the 'ndvidual coils of said springmember, said plug member further having a width approximately equal 'to the major axis 'of said elliptical cross section to cause torsional displacement of spaced coils relative to one another upon' insertion of said plug'member into said spring member,

whereby contact pressure between said edges and said vidual coils disposed in interlaced relationship with the coils of said spring' member.

4. An electrical connectoras set forth in claim l wherein the major aXes of adjacent coils of said spring member are disposed at *progressively difierent angular positions about the longitudinal aXis of said spring member, to' produce a twisted shape in said spring member in the 'ab'- sence of said plug member.

5. An electrical Connector comprising. at least one helically Wound metal springjmember having an elliptical cross sectionwhen-viewed axially thereof, and at least ,one elongate metal plug member adapted'for insertion into said spring member, said plug member being aXially-twisted, said plug member havinga set of opposite edges for engaging the individual coils of said spring member, said plug member further having a Width sertion into said spring member, one of said members approxmately equal to the major axis of 'said elliptical i cross section to cause torsional displacement of spaced. *coils relative to one another upon insertion of sad plug member into; said spring member, whereby contact pressaid torsionalVdisplacement'of said spring member.:

6. An electrical Connector comprising .at least one y helically, wound metal spring memberhaving an ellipticalcross section when viewed axially thereof; said i spring member being oaxially twisted when in `an unbiased condition, and ,at least one elongate metal plug member adapted for insertion into said spring member,

'said plug member having a set of opposite edges'for engaging the individual coils of said spring member, ,said i plug member further'having a Width approximately equal placement of said spring member. 7. An, electrical Connector com'prising at least one helically wound metal spring member having an elliptical cross section when viewed axially thereof, and at least one elongate metal plug member adapted for insertion into said spring member, one of said members being.

-axially'twisted, said plug member having a set ofpopposite edges for engaging the individual coils of said spring member, and a' longitudinal slot between said edges, said plug'member further having a Width approximately equal to the major aXis of said' elliptical cross section to cause torsional displacement of spaced coils relative to one another upon insertion of said plug member into said spring member, whereby contact pressure between said edges and said coils after insertion of said plug member into said spring member is aforded byosaid torsional displacemento said spring member.

8. An` electrical connecter comprising at least 'one helically wound metal spring member having an elliptical cross section when viewed aXially thereof, at least one elongate metal plug member adapted for insertion into said spring member, one of said members being aXially twisted, and a terminal member coupled with said spring member, said terminalmember being provided with a conca've end for receiving an end of 'said plug member in cooperative electrical contact therewith, said plug member having a set of opposte edges for engaging i V the individual' coils of said spring member, said "plug into said spring member is afforded by said torsional-displacement of said spring member. i

9.` An electrical connector comprising a helicallywound metal spring member having an elliptcal cross section when viewed axially thereof, said spring member omi prising a plurality of springs having their individual coils disposed in interlaced relationship with one another, and at least one elongatemetal plug member adapted torinbeing aXially twisted, said plug member having a set of opposite edges for engaging the individual coils of said spring member, said plug member further having a width approximately equal to the major aXis of said elliptic al cross section to cause torsional displacemenfof spaced coils relative to one another upon insertion of sad plug i member into said spring member, whereby contact pressurebetween said edges and saidcoilsj after insertion =of said plug member: into said spring member is afforded by'j "said torsional displacement of said spring'member. p

' Referencesicited by the Examiner i V ,UNITED STATES PATENTS I, 1392558 10/21 Darrah et al; 339 43 X' 2,427,0o1 79/47 Hubbell et ai, 339 256 x 2,924,so7 i 2/60' Field ,339475 2,9s2,935 5/611 Barnard 33947, 3,o5.s,os3 10/62 1 Schneider ssg zssx FOREIGN PATENTS 227,1o1 12/25, GreatBritain. 621,8l1 4/49 Great Britain.` V %7,302 3 /50 France.: 1,013,561 4/5 2 France.-

M. HENSON woon, JR., 'Primary xaminen' v -JOSEPH n snnns, Exam'ner, j

&B -r ai. 

1. AN ELECTRICAL CONNECTOR COMPRISING AT LEAST ONE HELICALLY WOUND METAL SPRING MEMBER HAVING A PORTION WITH AN ELLIPTICAL CROSS SECTION, AND AN ELONGATE METAL PLUG MEMBER ADAPTED FOR INSERTION INTO SAID SPRING MEMBER, ONE OF SAID MEMBERS BEING AXIALLY TWISTED, SAID PLUG MEMBER HAVING A SET OF OPPOSITE EDGES FOR ENGAGING THE INDIVIDUAL COILS OF SAID SPRING MEMBER, SAID PLUG MEMBER FURTHER HAVING A WIDTH APPROXIMATELY EQUAL TO THE MAJOR AXIS OF SAID ELLIPTICAL CROSS SECTION TO CAUSE TORSIONAL DISPLACEMENT OF SPACED COILS RELATIVE TO ONE ANOTHER UPON INSERTION OF SAID PLUG MEMBER INTO SAID SPRING MEMBER, WHEREBY CONTACT PRESSURE BETWEEN SAID EDGES AND SAID COILS IS PRODUCED BY SAID TORSIONAL DISPLACEMENT UPON INSERTION OF SAID PLUG MEMBER AS AFORESAID. 